diff --git a/src/ShellCheck/AnalyzerLib.hs b/src/ShellCheck/AnalyzerLib.hs
index 90a79e0..37a96ad 100644
--- a/src/ShellCheck/AnalyzerLib.hs
+++ b/src/ShellCheck/AnalyzerLib.hs
@@ -380,10 +380,6 @@ isParentOf tree parent child =
 
 parents params = getPath (parentMap params)
 
-pathTo t = do
-    parents <- reader parentMap
-    return $ getPath parents t
-
 -- Find the first match in a list where the predicate is Just True.
 -- Stops if it's Just False and ignores Nothing.
 findFirst :: (a -> Maybe Bool) -> [a] -> Maybe a
diff --git a/src/ShellCheck/Checks/Commands.hs b/src/ShellCheck/Checks/Commands.hs
index 93720e8..6c82a4f 100644
--- a/src/ShellCheck/Checks/Commands.hs
+++ b/src/ShellCheck/Checks/Commands.hs
@@ -484,7 +484,7 @@ prop_checkInteractiveSu4 = verifyNot checkInteractiveSu "su root < script"
 checkInteractiveSu = CommandCheck (Basename "su") f
   where
     f cmd = when (length (arguments cmd) <= 1) $ do
-        path <- pathTo cmd
+        path <- getPathM cmd
         when (all undirected path) $
             info (getId cmd) 2117
                 "To run commands as another user, use su -c or sudo."
diff --git a/src/ShellCheck/Fixer.hs b/src/ShellCheck/Fixer.hs
index c1f52a7..22b528b 100644
--- a/src/ShellCheck/Fixer.hs
+++ b/src/ShellCheck/Fixer.hs
@@ -97,6 +97,7 @@ instance Semigroup Fix where
             fixReplacements = fixReplacements f1 ++ fixReplacements f2
             }
 
+-- Conveniently apply a transformation to positions in a Fix
 mapPositions :: (Position -> Position) -> Fix -> Fix
 mapPositions f = adjustFix
   where
@@ -110,6 +111,26 @@ mapPositions f = adjustFix
             fixReplacements = map adjustReplacement $ fixReplacements fix
         }
 
+
+-- A replacement that spans multiple line is applied by:
+-- 1. merging the affected lines into a single string using `unlines`
+-- 2. apply the replacement as if it only spanned a single line
+-- The tricky part is adjusting the end column of the replacement
+-- (the end line doesn't matter because there is only one line)
+--
+--   aaS  <--- start of replacement (row 1 column 3)
+--   bbbb
+--   cEc
+--    \------- end of replacement (row 3 column 2)
+--
+-- a flattened string will look like:
+--
+--   "aaS\nbbbb\ncEc\n"
+--
+-- The column of E has to be adjusted by:
+-- 1. lengths of lines to be replaced, except the end row itself
+-- 2. end column of the replacement
+-- 3. number of '\n' by `unlines`
 multiToSingleLine :: [Fix] -> Array Int String -> ([Fix], String)
 multiToSingleLine fixes lines =
     (map (mapPositions adjust) fixes, unlines $ elems lines)
@@ -136,42 +157,6 @@ applyFix fix fileLines =
     let (adjustedFixes, singleLine) = multiToSingleLine [fix] fileLines
     in lines . runFixer $ applyFixes2 adjustedFixes singleLine
 
--- A replacement that spans multiple line is applied by:
--- 1. merging the affected lines into a single string using `unlines`
--- 2. apply the replacement as if it only spanned a single line
--- The tricky part is adjusting the end column of the replacement
--- (the end line doesn't matter because there is only one line)
---
---   aaS  <--- start of replacement (row 1 column 3)
---   bbbb
---   cEc
---    \------- end of replacement (row 3 column 2)
---
--- a flattened string will look like:
---
---   "aaS\nbbbb\ncEc\n"
---
--- The column of E has to be adjusted by:
--- 1. lengths of lines to be replaced, except the end row itself
--- 2. end column of the replacement
--- 3. number of '\n' by `unlines`
--- Returns the original lines from the file with the replacement applied.
--- Multiline replacements completely overwrite new lines in the original string.
--- e.g. if the replacement spans 2 lines, but the replacement string does not
--- have a '\n', then the number of replaced lines will be 1 shorter.
-replaceMultiLines rep fileLines = -- this can replace doReplace
-    let startRow = fromIntegral $ (posLine . repStartPos) rep
-        endRow =  fromIntegral $ (posLine . repEndPos) rep
-        (ys, zs) = splitAt endRow fileLines
-        (xs, toReplaceLines) = splitAt (startRow-1) ys
-        lengths = fromIntegral $ sum (map length (init toReplaceLines))
-        newlines = fromIntegral $ (length toReplaceLines - 1) -- for the '\n' from unlines
-        original = unlines toReplaceLines
-        startCol = ((posColumn . repStartPos) rep)
-        endCol = ((posColumn . repEndPos) rep + newlines + lengths)
-        replacedLines = (lines $ doReplace startCol endCol original (repString rep))
-    in
-    xs ++ replacedLines ++ zs
 
 -- start and end comes from pos, which is 1 based
 prop_doReplace1 = doReplace 0 0 "1234" "A" == "A1234" -- technically not valid